Electrochemical Nozaki–Hiyama–Kishi Coupling: Scope, Applications, and Mechanism
作者:Yang Gao、David E. Hill、Wei Hao、Brendon J. McNicholas、Julien C. Vantourout、Ryan G. Hadt、Sarah E. Reisman、Donna G. Blackmond、Phil S. Baran
DOI:10.1021/jacs.1c03007
日期:2021.6.30
practical using an electroreductive manifold. Although early studies pointed to the feasibility of such a process, those precedents were never applied by others due to cumbersome setups and limited scope. Here we show that a carefully optimized electroreductive procedure can enable a more sustainable approach to NHK, even in an asymmetric fashion on highly complex medicinally relevant systems. The e-NHK
最常用的 C-C 键形成方法之一是使用还原歧管,使卤乙烯与 Ni 和 Cr 催化的醛偶联(Nozaki-Hiyama-Kishi,NHK)变得更加实用。尽管早期研究指出了这种过程的可行性,但由于设置繁琐且范围有限,这些先例从未被其他人应用。在这里,我们展示了经过精心优化的电还原程序可以使 NHK 采用更可持续的方法,即使在高度复杂的医学相关系统上以不对称方式也是如此。当传统化学技术失败时,e-NHK 甚至可以使非规范底物类别(例如氧化还原活性酯)参与低负载量的 Cr。详细的动力学、循环伏安法、
Zirconocene−Zinc Transmetalation and in Situ Catalytic Asymmetric Addition to Aldehydes
作者:Peter Wipf、Seth Ribe
DOI:10.1021/jo9811827
日期:1998.9.1
On Ni Catalysts for Catalytic, Asymmetric Ni/Cr-Mediated Coupling Reactions
作者:Xiang Liu、Xiaoyong Li、Yu Chen、Yimin Hu、Yoshito Kishi
DOI:10.1021/ja302177z
日期:2012.4.11
The importance of the Ni catalyst in achieving catalytic asymmetric Ni/Cr-mediated coupling reactions effectively is demonstrated. Six phenanthroline-NiCl2 complexes 1a-c and 2a-c and five types of alkenyl iodides A-E were chosen for the study, thereby demonstrating that these Ni catalysts display a wide range of overall reactivity profiles in terms of the degree of asymmetric induction, geometrical isomerization, and coupling rate. For three types of alkenyl iodides A-C, a satisfactory Ni catalyst(s) was found within 1a-c and 2a-c. For disubstituted (Z)-alkenyl iodide D, 2c was identified as an acceptable Ni catalyst: in terms of the absence of Z --> E isomerization and the degree of asymmetric induction but not in terms of the coupling rate. Two phosphine-based Ni catalysts, [(Me)(3)P](2)center dot NiCl2 and [(cy)(3)P](2)center dot NiCl2, were found to meet all three criteria for D. The bond-forming reaction at the C16-C17 position of palytoxin was used to demonstrate the usefulness of the Ni catalysts thus identified.
Preparation of Stereodefined Homoallylic Amines from the Reductive Cross-Coupling of Allylic Alcohols with Imines
作者:Ming Z. Chen、Martin McLaughlin、Masayuki Takahashi、Michael A. Tarselli、Dexi Yang、Shuhei Umemura、Glenn C. Micalizio
DOI:10.1021/jo101535d
日期:2010.12.3
provide a means to translate the stereochemical information of the allylic alcohol to the homoallylic amine or to control diastereoselection in the coupling reactions of achiral allylic alcohols with chiralimines. Double asymmetric coupling reactions are also described that afford a unique means to control stereoselection in these complex convergent coupling processes. Finally, empirical models are
Asymmetric synthesis of allylic secondary alcohols: a new general approach for the preparation of α-amino acids
作者:Lorna J. Drummond、Andrew Sutherland
DOI:10.1016/j.tet.2010.05.066
日期:2010.7
A new general approach for the synthesis of opticallyactiveα-amino acids has been developed. The key steps involve a ruthenium catalysed cross-coupling reaction to give a range of α,β-unsaturated ketones, which were then reduced to allylic secondary alcohols in the presence of a chiral CBS oxazaborolidine. A thermal Overman rearrangement was used to prepare a series of allylic trichloroacetimidates